Agricultural
Burning

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Prescribed fire has long been a useful management tool for
croplands, rangelands, and forests. As concern for air quality increases,
however, it becomes more important to ensure that intentional or prescribed
burning is used responsibly. EPA is working with the agricultural community
to devise reasonable, science-based policies that define the role of agricultural
burning in a way that allows efficient agricultural production as well
as a healthy environment.

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Background: Clean Air Act -- Title I

Pursuant to Title I of the CAA, EPA has established national ambient
air quality standards (NAAQSs) to limit levels of "criteria pollutants,"
including carbon monoxide, lead, nitrogen dioxide, particulate matter,
ozone, and sulfur dioxide.

EPA calls these pollutants "criteria air pollutants"
because the agency has regulated them by first developing health-based
criteria (science-based guidelines) as the basis for setting permissible
levels. One set of limits (primary standard) protects health; another
set of limits (secondary standard) is intended to prevent environmental
and property damage.

A geographic area that meets or does better than the primary
standard is called an attainment area; areas that don't meet the primary
standard are called nonattainment areas. A single geographic area may
have acceptable levels of one criteria air pollutant but unacceptable
levels of one or more other criteria air pollutants; thus, an area can
be both attainment and nonattainment at the same time.

Under Section 110 of the CAA, each state must develop a
State Implementation Plan (SIP) to identify sources of air pollution and
to determine what reductions are required to meet federal air quality
standards. A State Implementation Plan is a detailed description of the
programs a state will use to carry out its responsibilities under the
Clean Air Act.

Technical guidanceand data sources
EPA maintains a Clearinghouse
for Inventories and Emission Factors (CHIEF). The CHIEF web site
provides access to tools for estimating emissions of air pollutants
in various geographic domains (e.g. urban areas, regions, or the entire
nation). It serves as EPA's central clearinghouse for the latest information
on air emission inventories and emission factors. Emission estimation
data bases, newsletters, announcements, and guidance on performing inventories
are included in CHIEF.

The Factor
Information Retrieval (FIRE) Data System (one of the tools offered
by CHIEF) is a database management system containing EPA's recommended
emission estimation factors for criteria and hazardous air pollutants.
FIRE includes information about industries and their emitting processes,
the chemicals emitted, and the emission factors themselves. The FIRE
database is designed for use by local, state, and federal agencies,
environmental consultants, and others who require emission factor information
for estimating both criteria and toxic air emissions from stationary
sources.

Enforcement
The 1990 Clean Air Act gives important enforcement powers to EPA. It
used to be very difficult for EPA to penalize a company for violating
the Clean Air Act. The 1990 law enables EPA to fine violators.
Other parts of the 1990 law increase penalties for violating the Act
and bring the Clean Air Act's enforcement powers in line with other
environmental laws.

Air Emissions From Agricultural
Practices

Under Section 110 of the CAA, each state must develop a State Implementation
Plan (SIP) to identify the sources of air pollution and to determine what
reductions are required to meet federal air quality standards.

State implementation plans are collections of the regulations
used by a state to reduce air pollution. The Clean Air Act requires that
EPA approve each state implementation plan. Members of the public are
given opportunities to participate in review and approval of state implementation
plans.

The degree to which ambient air emissions from farming practices
-- such as prescribed burning -- are allowed are location-specific (specific
to a geographic area) within each State Implementation Plan. Visibility
standards may also apply through the State Implementation Plan. Locations
that are in areas that have been classified as "nonattainment areas"
under the National Ambient Air Quality Standards are subject to more restrictions.

The U.S. Department of Agriculture (USDA) has established
the Agriculture Air Quality Task Force.
EPA is an active participant in the Task Force. The Task Force has unanimously
endorsed a listing of high priority research needs to improve the level
of understanding of the impact of agriculture on air quality levels.

On February 25, 1998, the USDA and EPA announced a Memorandum
of Understanding (MOU) to ensure that the two agencies work together to
provide a healthy environment with clean air in harmony with a strong
agriculturally productive nation. The MOU establishes a framework for
the two agencies to share expertise and a process for involving the agricultural
community in a cooperative effort to address agriculture-related air quality
issues, including emissions from agricultural burning.

EPA will work with the task force to refine the distinction
between wildland fires (which are covered by EPA's Interim Air Quality
Policy on Wildland and Prescribed Fires) and agricultural burning.

Prescribed Burning

Prescribed burning is a land treatment, used under controlled conditions,
to accomplish natural resource management objectives. It is one of several
land treatments, used individually or in combination, including chemical
and mechanical methods.

Prescribed fires are conducted within the limits of a fire
plan and prescription that describes both the acceptable range of weather,
moisture, fuel, and fire behavior parameters, and the ignition method
to achieve the desired effects. Prescribed fire is a cost-effective and
ecologically sound tool for forest, range, and wetland management. Its
use reduces the potential for destructive wildfires and thus maintains
long-term air quality. Also, the practice removes logging residues, controls
insects and disease, improves wildlife habitat and forage production,
increases water yield, maintains natural succession of plant communities,
and reduces the need for pesticides and herbicides.

The major air pollutant of concern is the smoke produced.
Smoke from prescribed fires is a complex mixture of carbon, tars, liquids,
and different gases. This open combustion source produces particles of
widely ranging size, depending to some extent on the rate of energy release
of the fire. The major pollutants from wildland burning are particulate,
carbon monoxide, and volatile organics. Nitrogen oxides are emitted at
rates of from 1 to 4 g/kg burned, depending on combustion temperatures.
Emissions of sulfur oxides are negligible.

Some pollution prevention practices that can be used during
prescribed burning operations include the following:

Carefully plan burning to adhere to weather, time of year, and fuel
conditions that will help achieve the desired results and minimize impacts
on water quality.

Intense prescribed fire for site preparation should not be conducted
in the streamside management areas.

Particulates

Particulate matter is the term for solid or liquid particles found
in the air. Some particles are large or dark enough to be seen, such as
soot or smoke. Others are so small they can be detected only with an electron
microscope.

Breathing particulate matter can cause serious health problems.
Particulates also reduce visibility in many parts of the United States.
They can also accelerate corrosion of metals and damage paints and building
materials such as concrete and limestone.

Sources of particulates
"Coarse" particles are larger than 2.5 micrometers and generally
come from sources such as vehicles traveling on unpaved roads, materials
handling, crushing and grinding operations such as cement manufacturing,
and combustion sources.

Particles less than 2.5 micrometers (0.0004 inch) in diameter
are known as "fine" particles. Fine particles result from
fuel combustion in motor vehicles, power plants and industrial facilities,
residential fireplaces, woodstoves, wildfires, and prescribed forest
burning. Fine particles can also be formed when combustion gases are
chemically transformed into particles.

Health effects of particulates
Particulate matter less than 10 micrometers in size, including fine
particles less than 2.5 micrometers, can penetrate deep into the lungs.
On a smoggy day, one can inhale millions of particles in a single breath.
Tens of millions of Americans live in areas that exceed the national
health standards for particulates.

In recent studies, exposure to particulate pollution --
either alone or with other air pollutants -- has been linked with premature
death, difficult breathing, aggravated asthma, increased hospital admissions
and emergency room visits, and increased respiratory symptoms in children.
People most at risk from exposure to fine particulate matter are children,
the elderly, and people with chronic respiratory problems.

Environmental effects of particulates
Fine particles scatter and absorb light, creating a haze that limits
our ability to see distant objects. Particle plumes of smoke, dust,
and/or colored gases that are released to the air can generally be traced
to local sources such as industrial facilities or agricultural burning.
Regional haze is produced by many widely dispersed sources, reducing
visibility over large areas that may include several states.

The Clean Air Act established special goals for visibility
in some national parks and wilderness areas. In 1994, EPA began developing
a regional haze program that is intended to ensure that continued progress
is made toward the national visibility goal of "no manmade impairment."
Such control efforts would likely result in improved public health protection
and visibility in areas outside national parks as well.